Perry's Index to the Aesopica

Fables exist in many versions; here is one version in English:

THE TUNA FISH AND THE DOLPHIN

A tuna fish who was being chased by a dolphin was splashing madly through the
water. Just when the dolphin was about to catch him, the tuna fish heaved himself
forward with a great effort and landed on an island. Matching his effort, the
dolphin ran aground beside him. The tuna fish then turned to look at the gasping
dolphin and said, 'I do not grieve over my own death, so long as I am able to
see that the one to blame is dying together with me!' The fable shows that people readily undergo a disaster when they can witness
the destruction of those who are to blame.

Source:
Aesop's Fables. A new translation by Laura
Gibbs.
Oxford University Press (World's Classics): Oxford, 2002.
NOTE: New
cover, with new ISBN, published in 2008; contents of book unchanged.

You can find a compilation of Perry's index to the Aesopica in the gigantic appendix to his
edition of Babrius and Phaedrus for the Loeb Classical Library
(Harvard University Press: Cambridge, 1965). This book is an absolute must for anyone interested
in the Aesopic fable tradition. Invaluable.